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Sunday, May 31, 2015

LightSail Spacecraft Phones Home After Software Glitch

After a successful launch into orbit aboard a United Launch Alliance Atlas V rocket out of Cape Canaveral, The Planetary Society’s LightSail spacecraft went silent after two days of communications. The solar sailing spacecraft test mission, a precursor to a 2016 mission, has now resumed contact after a suspected software glitch affected communications. The LightSail team will soon determine when to attempt deployment of the spacecraft’s Mylar solar sails. "Our LightSail called home! It’s alive! Our LightSail spacecraft has rebooted itself, just as our engineers predicted. Everyone is delighted," said Bill Nye, CEO at The Planetary Society.

At 5:21 p.m. EDT (21:21 UTC) on Saturday, an automated radio chirp was received and decoded at the spacecraft's Cal Poly San Luis Obispo ground station. Another came in eight minutes later at 5:29 p.m. The real-time clock on board the spacecraft, which does not reset after a software reboot, read 908,125 seconds—approximately ten-and-a-half days since LightSail’s May 20 launch.

"Based upon the on-board timers contained within the beacon (and comparing them to beacons following deployment), it appears that a reboot occurred within the past day," wrote Georgia Tech professor David Spencer, LightSail’s mission manager. "Due to uncertainty in the orbit state (TLEs), our ability to reliably track the spacecraft is marginal at this point. Cal Poly is coordinating with international colleagues to arrange their support in acquiring beacon telemetry," he said.

The primary goal of this test flight is to practice the sail deployment procedure. A higher-altitude LightSail test, scheduled for next year, will provide an opportunity to steer a spacecraft by reflecting photons of light from the sun at various angles.

The technology was tested previously by Japan's Ikaros solar sail in 2010 and NASA's Nanosail-D spacecraft in 2011. The Planetary Society hopes that its LightSail project will lead to even more ambitious sun-powered space voyages. Eventually, solar sails could conceivably be used to propel spacecraft to the outer reaches of the solar system and beyond.